1. Field of the Invention
This invention relates to a head-up display apparatus installed in a vehicle and a mirror unit used therefor, especially, a head-up display apparatus, which is installed in an instrument panel and includes a mirror for reflecting an image of a display device toward a windshield, and a mirror unit used for the same.
2. Description of the Related Art
A head-up display apparatus, which reflects an image of a display device 5 installed in an instrument panel 1 toward a windshield 6 by a mirror 3c1 to make a vehicle driver recognize visually as shown in FIG. 2A, is installed in a vehicle. FIG. 2 is used for describing a related art, but is not a prior art.
A height of the instrument panel 1 is set a limit for safety. A space 7 in the instrument panel 1 is provided with many members, such as an air duct continuing to an air conditioner, reinforcing parts, wiring harnesses and the like.
The mirror 3c1 must be placed in the vicinity of the windshield 6 according to a shape or an angle of the windshield 6. In case, by reason of a height limit of the instrument panel 1, the mirror 3c1 must be placed to project a part of the mirror 3c1 from a line of the instrument panel 1 when in use.
Preferably, the mirror 3c1 of the head-up display apparatus is covered and protected from dust when not in use, mainly daytime. Therefore, a member for covering and protecting from dust the mirror 3c1 when not in use is required. Preferably, moving the whole mirror 3c1 downward in parallel and pushing the mirror 3c1 into the instrument panel 1, an upper area is covered by a cover. As mentioned above, number of members received in the instrument panel 1 is increasing, so that there is no space in the instrument panel for pushing the whole mirror 3c1 into the instrument panel.
Therefore, by reason of height limit of the instrument panel 1 and increasing members received in the instrument panel 1, the mirror 3c1 is placed at a position when in use, and the mirror 3c1 must be covered and protected from dust when not in use.
An example of a head-up display apparatus having a mirror reflecting an image of a display device for displaying a predetermined image toward a windshield is disclosed in a patent reference 1; Japan Patent 2002-331855.